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39 lines
809 B
Python
39 lines
809 B
Python
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'''
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Problem:
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The prime factors of 13195 are 5,7,13 and 29. What is the largest prime factor of a given number N?
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e.g. for 10, largest prime factor = 5. For 17, largest prime factor = 17.
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'''
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import math
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def isprime(no):
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if(no==2):
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return True
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elif (no%2==0):
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return False
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sq = int(math.sqrt(no))+1
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for i in range(3,sq,2):
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if(no%i==0):
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return False
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return True
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max=0
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n=int(input())
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if(isprime(n)):
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print n
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else:
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while (n%2==0):
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n=n/2
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if(isprime(n)):
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print n
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else:
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n1 = int(math.sqrt(n))+1
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for i in range(3,n1,2):
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if(n%i==0):
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if(isprime(n/i)):
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max=n/i
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break
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elif(isprime(i)):
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max=i
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print max
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